208th RQC Seminar

• 講演者

  Mr. Thomas Lagoutte - Ferre
  ( ENS Paris-Saclay )

• 日程

  2025年7月30日(水), 16:00 - 17:00 (4:00 p.m. - 5:00 p.m.)

• 開催場所

  ハイブリッド（ZOOM・ Wako Main Research 3F 345-347 Seminar Room / 研究本館3階 セミナー室 (345-347) (C01))

• 講演タイトル

  Controllable Low-Rank Quantum State Reconstruction via Neural Density Matrices

• お問合せ

  norilab_rqc_assist[at]ml.riken.jp

講演概要
Quantum state reconstruction is essential for characterizing quantum systems, yet it remains particularly challenging for mixed states and large-scale systems. This study introduces a method for controllable low-rank quantum state reconstruction using neural density matrices. By embedding mixed quantum states into an enlarged Hilbert space through purification with auxiliary degrees of freedom, the approach enables precise control over the rank of the reconstructed density matrix via the number of ancillary units. The method employs various optimization techniques to train the neural network and is validated on experimental data from trapped-ion systems. Results show that the approach accurately reconstructs dominant eigenstates and offers a scalable solution for quantum state tomography. However, the recovery of dominant eigenstates is sensitive to the choice of loss function, underscoring its critical role in low-rank approximation accuracy. While the method demonstrates promise, challenges persist in recovering subdominant eigenstates and scaling to larger systems. Future work will focus on optimizing loss function selection and addressing scalability to further enhance low-rank quantum state reconstruction.